Barry2 

Well that’s interesting.
BTinNYC , can you please answer the following…

Bike?
Rear Derailleur type?
Cassette type & tooth count?

Thanks

Barry

GhostRider62

Not sure if this might help. I run SRAM Rex AXS RD with either a Rotor or Shimano Ultegra 12 speed cassette. Hanger alignment and adjustment of the RD is critical. I get weird skipping on both cassettes if either are off slightly but the real culprit was the chain I tried YNB, Campy SR, and then finally what seems to cause fewer problems is the KMC. I cannot remember if it was the 5th cog on the Ultegra but I think it was. It happens much less frequently with the KMS chain.......or maybe the cassette defect is wearing out. I had that same problem back pedaling as shown in the video and it was only on one cog. Sorry, I cannot recall which one but it was in the middle of the range.

Barry2 

Sorry, I didn’t make it clear, the video is not “back peddling”, I committed the ultimate sin and turned the bike upside down.
I did note that in the YouTube notes, but not if you watch the vid on this site. I’ll go fix that.

Thanks for noticing

Barry

BTinNYC 

​Canyon Endurace
RD-8150 VIA (not sure if the VIA matters)
11-34 Ultegra
Good luck.

The_hump_

TakingMyTime

Canyon Eendurace Ultegra 12 speed Di2 11/34 cassette 50/34 Chainrings

I was reading this thread and not thinking much of it. Then, yesterday while checking my Front Der alignment (new bike) I had the opportunity to be in the large chainring and biggest (34 tooth) cog and I was getting the same clicking sound. Mine was in almost one after another (only 2 clicks) and not spaced out over the cassette. This could have been from the extreme cross-chaining position but I plan on investigating further.

REDMASTA

sounds bad make sure to wear a helmet

Barry2 

The_hump_ ,
Have you had the time yet too see if your chain is hanging just like mine does in the video I provided ?

Thanks

Barry

TakingMyTime

Mine went away with a slight RD adjustment to the outside using the Shimano app. While inspecting it closer my top pulley was clicking/jerking at the same time and that got me thinking this thing probably just needs an alignment. Hope this helps.

TakingMyTime

Well, sorry to keep this thread going but... the RD adjustment didn't cut it. At first I thought I'd fix it but it's still there. It is so noticeable that the guy I was riding with could hear it. I would have it in the 5th cog (making noise) and when I shifted to 4th or 6th it went away. It went away enough to be noticed by this other rider. My only guess is that it may be a "B" adjustment screw setting. Under first inspection the chain seems to be jerking between the top pulley and the cassette at the point of "noise". I went on a pretty dirty ride yesterday so this morning the cassette is coming off and getting a surgical cleaning. I will also ensure that all spacers etc are in the correct order when reassembling. Then start playing with the B screw.

Barry2 

If your top pully is jerking as you very slowly rotate pedals, it is very likely the "B" screw not far enough in.
Mine did the same when I went from 11-30 to 11-34 12sp cassettes.

Barry

TakingMyTime

^^Thanks for the support^^ I just moved it in 1 full turn. I'm going to take it a little at a time in order to try and find the sweet spot (if there is any). I'm going to take it for a spin later this afternoon.

willy757

I have the EXACT same problem. Did you find a solution ?

Barry2 

Welcome to Bike Forums.
I replaced my noisy Ultegra 12sp 11-34 with a Dura Ace 11-34.
At first the DA did click, but just barely audible.
After some use, no click at all.

Barry

willy757

thanks for the quixi reply Barry.

I've ahd the same issue from day one on a new Dura Ace 12 speed, its driving me crazy

Barry2 

willy757
Are you sure the cassette is DA?
Have you checked the "B" screw adjustment?

Barry

willy757

Yes defo DA
The B screw looks fine and the issue is only when I'm in the big ring and mid cassette

Barry2 

Mine was only when using cog #5 (21T) and it occurred when using either small or large rings.

Barry

phuvf

HI all - joined this forum as I have exactly the same issue, in my case on a new Canyon Endurace Ultegra 12-speed.

On my bike the issue appears to be not with the 21t cog itself, but with the 19t cog below it. When in the 21t cog, some of the teeth on the 19t are very close to the outer chainplates and this causes the chain the hang briefly when engaging with the 21t. There's two sets of teeth on the 19t that cause this issue, hence the twice-per-revolution ticking noise when riding.

I fixed this by filing a bit off the back of the offending teeth on the 19t cog using a needle file with a smooth back (so as not to damage the 21t cog). For now this appears to have worked, but I'll need to test some more yet.

I have photos etc. but am new to the forum, so can't post photos or URLs. Message me I guess (?) and I'll send you a link to the piccies.

sege

I'm having exactly same issue, first day with my Canyon Endurace Ultegra Di2, could you kindly send me photos with the fix, that clicking gets me crazy.. I can't DM you as I'm a new member.

Barry2 

sege
Welcome to bike forums.
With this thread there have been several symptoms reported and we can’t tell which yours is replicating.

in future posts you can ask the question of a person by typing @Their-name and picking them from the pop-up list.
This will notify them, even if they have unsubscribed from the thread.

If you were asking me, I replaced the Ultegra cassette with Dura ace. The double click was still there but very quiet. After a some miles the clicks were gone.

Barry